The invention relates in general to latch needles used in knitting machines, and in particular to a method of closing dial needle latches to ensure transfer of a loose loop of yarn from the shank portion of the dial needle to an associated cylinder needle.
The invention finds particular use in the circular rib knitting of non-stretch yarns of cotton or wool wherein a non-shank hugging loose loop, spaced from the latch side of the dial needle, cannot be relied on to flip the open dial needle latch to a closed position as the dial needle is withdrawn through the loose loop. If an attempt is made to withdraw an open latch dial needle through a loose loop about its shank portion, the exposed hook of the dial needle may snag the loose loop even though the spoon portion of the open latch clears the loose loop on its withdrawal, thus resulting in a knitting defect.
While mechanical abutments, fingers, or the like could be utilized to close the latches of the dial needles, the severe space constraints in the needle area of a circular rib knitting machine would most probably preclude the successful use of mechanical latch closing means.
The use of non-mechanical means for effecting latch movement, such as use of an air blast, is illustrated by U.S. Pat. Nos. 2,658,366 and 4,033,149. While these patents disclose the use of air flow to move needle latches, they do not deal with the problem of loose loop transfer of non-stretch yarn as noted above.